Use of the heat of vaporization of a fuel as an air-conditioning medium for a vehicle

ABSTRACT

The energy required to vaporize a liquid fuel, such as liquid natural gas, of a vehicle is used to cool water in a loop. The cooled water is passed through a heat exchanger for heat exchange with air to cool the latter to effect air conditioning. A thermostatically controlled valve admits engine-cooling water to the loop when there is a danger of freezing of the water in the loop. The loop is also used when it is desired to heat the vehicle. During heating, engine-cooling water is admitted to the heat exchanger, passes through the loop to perform its vaporizing function, and then goes out a recirculating line for return to the radiator.

United States Patent Me] ones Feb.8,1972

[54] USE OF THE HEAT 0F VAPORIZATION OF A FUEL AS AN AIR-CONDITIONINGMEDIUM FOR A VEHICLE [21] Appl. No.: 19,279

[52] [1.8. Cl ..165/23, 165/43 [51] Int. Cl ..B60h 3/04 [58] Field ofSearch ..l65/22, 23, 27, 42, 43, 44

[56] References Cited UNITED STATES PATENTS 2,028,069 1/1936 Horton..165/43 2,751,155 6/1956 Collat ..l65/22 Primary ExaminerCharles SukaloAttorney-Christie, Parker & Hale {57] ABSTRACT The energy required tovaporize a liquid fuel, such as liquid natural gas, of a vehicle is usedto cool water in a loop. The cooled water is passed through a heatexchanger for heat exchange with air to cool the latter to effect airconditioning. A thermostatically controlled valve admits engine-coolingwater to the loop when there is a danger of freezing of the water in theloop. The loop is also used when it is desired to heat the vehicle.During heating, engine-cooling water is ad mitted to the heat exchanger,passes through the loop to perform its vaporizing function, and thengoes out a recirculating line for return to the radiator.

6 Claims, 1 Drawing Figure I 1 @0 2e i 33 40 5% a 4 JV e l|| 56 25 Qi l643 BACKGROUND OF THE INVENTION The present invention relates to airconditioning and heating of the passenger compartment of vehicles ingeneral and, more in particular, to the use of heat energy extractedduring the vaporization of fuel to air-condition the compartment whendesired, and, when heating is desired, to use the enginecooling water tovaporize the fuel and to heat the vehicle.

For some years liquid petroleum gas has been used as an alternate fuelfor the internal combustion engine of a vehicle. Recently natural gashas become an alternate fuel to gasoline primarily because the exhaustgas emissions from a natural gas powered vehicle are very low in thepollutants of oxides of nitrogen, hydrocarbons and carbon monoxide. Oneof the ways of storing natural gas in a vehicle is to contain it inliquid form in a cryogenic container.

Liquefied natural gas must be vaporized before it is used as a fuel.Similarly, liquefied petroleum gas must be vaporized. The vaporizationof these fuels requires heat energy. This fact has been used in thepast, at least for liquefied petroleum gas, to provide cooling of thepassenger compartment of a vehicle.

SUMMARY OF THE INVENTION The present invention provides an improvedsystem for cooling the passenger compartment of a vehicle wherein theworking fluid employed in an engines cooling fluid usually is water withor without antifreeze. The system also vaporizes the vehicles fuel. Inpreferred form, the present invention also provides means to prevent theworking fluid from freezing and means to heat the passenger compartmentthrough the use of the same fluid used to vaporize the fuel.

In one form, the present invention contemplates a closedloop heatexchange system including a vaporizer for vaporizing the vehicles fueland a heat exchanger for cooling passenger compartment air. The loopemploys engine-cooling water as its working fluid. A thennostaticelement is preferably provided to sense the temperature of the water ofthe loop as it leaves the vaporizer. In this preferred form, a valvecontrolled by the thermostatic element is disposed to admit radiatorwater from the vehicles engine to the loop in the event that thetemperature of the water in the loop lowers to a predetermined value of,say, 35 F. Means are also provided for storing the engine fuel, such asa cryogenic tank if the engine fuel is liquid natural gas. A pump in theloop is provided to circulate the working fluid.

A specific form of the present invention contemplates the use of thevehicles passenger compartment heater as the heat exchanger in the loop.A heater valve is disposed to admit engine-cooling water from the engineto the heat exchanger when it is desired to heat the passengercompartment. A check valve is provided to prevent water being admittedto the loop from the engine from bypassing the heat exchanger by passingthrough recirculating line means from the loop to the engines radiator,the recirculating line means being provided to recirculateengine-cooling water to the engine when the loop is receiving water fromthe engine.

The present invention provides a vehicle-cooling system which serves thefunction of cooling the vehicle while vaporizing a fuel such as liquidnatural gas used with the vehicles engine. The thermostat and itscontrolled valve prevent the working fluid used to vaporize orvolatilize the fuel and to cool the passenger compartment of a vehiclefrom freezing. In its more particular form the present inventionprovides a simple and expedient means of coupling the cooling andvaporizing function with a vehicles heater. In the latter instance thevolatilizing requirement is still effected even though the system isheating the passenger compartment.

These and other features, aspects and advantages of the presentinvention will become more apparent from the following description,appended claims and drawing.

BRIEF DESCRIPTION OF THE FIGURE The single FIGURE is a schematic diagramof the cooling and heating system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the FIGURE, asystem is shown for vaporizing the fuel used to power a vehicle and toeither cool or heat the passenger compartment of the vehicle.

The system includes a working fluid loop 10 consisting in general of aheat exchanger 12, a pump 14, a vaporizer 16, a thermostatic element 18and a check valve 20.

In greater detail, a line 22 of loop 10 leads from the outlet side ofheat exchanger 12 to pump 14. The outlet of the pump is connected to aline 24 which leads to an inlet to a working fluid side 25 of vaporizer16. An outlet line 26 leads from the working fluid side of vaporizer 16and contains thermostatic element 18 and check valve 20. Loop 10normally employs as a working fluid engine-cooling water with or withoutnormal additives such as antifreeze.

The fuel illustrated for powering an engine 28 of the vehicle is liquidnatural gas. The fuel is contained in the cryogenic vessel 30. A line 32leads from this vessel to a fuel side 34 of vaporizer 16. An outlet line36 leads from the fuel side of the vaporizer to a fuel-air mixer ofengine 28.

Vaporizer 16 is of standard construction and functions to vaporize theliquid natural gas by heat exchange with engine cooling water in loop10. The engine-cooling water in loop 10 is cooled by the exchange ofheat energy with the vaporizing fuel. The cooling is considerableinasmuch as there is a relatively large amount of energy required tochange the state of the liquid natural gas from liquid to vapor.

Heat exchanger 12 is preferably a standard vehicle passenger compartmentheater which may take the fonn of a radiator. A fan 38 is used tocirculate air through the heat exchanger to cool passenger compartmentair or, altematively, to heat it. Fan 38 is driven by a motor 40 whichgets its power from the vehicle s electrical system.

Thennostatic element 18 controls a solenoid valve 42. The solenoid valveis in fluid circuit through a line 44 with loop 10 and the cooling waterpassages of engine 28, the latter circuit being completed through a line46 emanating from the cooling passages of the engine.

Solenoid valve 42 is normally closed. A spring 48 maintains the valveclosed until a solenoid 50 is energized. Upon the energization of thesolenoid, a valving element 52 of the solenoid valve is shifted to openthe valve. Solenoid 50 is in series electrical circuit with athermostatically controlled, normally open switch 54. Normally openswitch 54 is in turn in series circuit with a source of power such as avehicle battery 56. Normally open switch 54 is controlled bythermostatic element 18.

The thermostatic element is set to close normally open switch 54 whenthe temperature of the engine-cooling water in loop 10 leaving vaporizer16 is about, say, 35 F., that is, when the temperature of the waterleaving the vaporizer approaches its freezing point. Pump 14 ispreferably powered by an electric motor, not shown. The motor canreadily be run by the vehicle s electrical system.

A heater valve 58 is disposed in line 46. Line 46 is connected in fluidcircuit with line 26 of loop 10 between an inlet 60 of heat exchanger 12and check valve 20. A recirculating line 62 is disposed betweenthermostatic element 18 and check valve 20, and leads to the enginescooling system, as between the outlet of a radiator 64 of the engine andthe engine itself.

Check valve 20 is disposed to admit to fluid circulation around loop 10only in a counterclockwise direction. As such, engine-cooling wateradmitted to the loop through heater valve 58 is forced through heatexchanger 12, rather than into line 26 and out recirculating line 62.

The operation of the system will initially be described for cooling of apassenger compartment of a vehicle. For cooling of the passengercompartment, heater valve 58 is closed. Under normal conditions solenoidvalve 42 is also closed, pump 14 is energized and engine 28 is running.Liquid natural gas will pass from vessel 30 into vaporizer 16 where itis vaporized. The vaporized gas leaves vaporizer 16 to power the engine.During vaporization, engine-cooling water in loop will be cooled. Thiswater will continuously circulate around the loop for passage into andout of heat exchanger 12 and vaporizer l6, and is not circulated throughthe engines cooling system. During its passage through heat exchanger 12the water passes in heat exchange relationship with air being driventhrough the heat exchanger by fan 38. This air is cooled and is used inthe passenger compartment of the vehicle. The relatively warm waterleaving the heat exchanger enters the vaporizer where it is once againcooled. Pump 14 effects the circulation of engine-cooling water in loop10.

In the event that the temperature of the engine-cooling water in loop 10approaches its freezing temperature as it leaves vaporizer 16, say thewater approaches 35 F., thermostatic element 18 will close normally openswitch 54. With switch S4 closed, a circuit to solenoid 50 of solenoidvalve 42 is established. With this circuit established, the solenoidvalve opens momentarily to admit relatively warmer engine-cooling waterfrom engine 28 to loop 10. While solenoid valve 42 is open to admit thisrelatively warmer water to the loop, water can leave the loop throughrecirculating line 62. The water leaving the loop is passed into thecooling system of engine 28 as at the outlet of radiator 64.

Under normal circumstances very little water will be admitted throughsolenoid valve 42 into loop 10 because very little water is needed toraise the temperature of the fluid in the loop to above the temperaturerequired to actuate thermostatic element 18.

In the event that it is desired to provide heat within the passengercompartment of the vehicle, heater valve 58 is opened. With the openingof heater valve 58, heated engine-cooling water from engine 28 passesthrough line 46 into heat exchanger 12, check valve 20 preventing thiswater from entering line 26 and returning to the engine through line 62.This water passes in heat exchange relationship with air forced throughthe heat exchanger fan 38 to heat the air and the passenger compartment.The water leaving the heat exchanger will pass under the influence ofpump 14 into vaporizer 16 where it will be cooled while supplying theheat required to vaporize fuel from vessel 30. The relatively cool waterleaving the vaporizer will then pass through recirculating line 62 backto the radiator.

The system of the present invention provides a very simple and effectivemeans for vaporizing an engine 5 fuel while serving a passengercompartment heating or cooling function. Through the use of athermostatic element at the outlet of the systems vaporizer to controlthe admission of warm enginecooling water to the working loop of thesystem, there is no risk that the working fluid will freeze. As aconsequence, the function of the vaporizer is always assured andreliable air conditioning effected. Moreover, switching from airconditioning to heating is very simply accomplished with the use of asingle valve. Thus, extensive and complicated system ele ments areavoided.

The present invention has been described with reference to a certainpreferred embodiment. The spirit and scope of the appended claims shouldnot necessarily, however, be limited to the foregoing description.

What is claimed is:

l. A fluid circuit for vaporizing a fuel for a water-cooled engine of avehicle while cooling or heating a passenger compartment of the vehiclecomprising:

a. means for storing a source of fuel to be vaporized;

b. a vaporizer for vaporizing fuel through heat exchange with a workingfluid of engine-cooling water, the vaporizer being in fluid circuit withthe fuel-storing means;

c. a selectively closed fluid loop circuit for the working fluid;

d. a heat exchanger in the loop for exchanging heat energy between theworking fluid and air, the heat exchanger being adapted for discharge ofsuch air into the passenger compartment of the vehicle and being influid circuit with the vaporizer;

e. a pump in the loop in fluid circuit with the vaporizer and the heatexchanger for circulating working fluid around the loop;

. selectively actuatable, normally closed valve means for admitting warmengine-cooling water from the engine to the loop;

g. means for recirculating engine-cooling water from the loop to theengines cooling system when the valve means is open and after waterentering the loop from the engines cooling system passes through theheat exchanger and the vaporizer;

h. thermostatic element means for sensing the temperature of the workingfluid in the loop;

i. second selectively actuatable, normally closed valve means foradmitting warm engine-cooling water from the engine to the loop; and

j. means coupling the thermostatic element means with the second valvemeans to open the valve means to admit warm engine-cooling water intothe loop upon the sensing of a predetermined working fluid temperaturenear its freezing point by the thermostatic element, the recirculatingmeans being operable to pass engine-cooling water from the loop when thesecond valve means is open.

2. The circuit claimed in claim 1 wherein the second valve means isdisposed in fluid circuit with the loop between the working fluid inletof the vaporizer and the outlet of the heat exchanger.

3. The circuit claimed in claim 2 wherein the first valve means isdisposed in fluid circuit with the loop between the inlet of the heatexchanger and the working fluid outlet of the vaporizer.

4. The circuit claimed in claim 3 including check valve means betweenthe recirculating means and the first valve means to prevent water fromsuch valve means from bypassing the heat exchanger.

5. A system for vaporizing a fuel such as liquid natural gas used topower an engine of a vehicle while providing cooling air to the vehiclespassenger compartment comprising:

a. a vaporizer for vaporizing the fuel as it leaves a fuel container ofthe vehicle;

b. means for circulating a working fluid in a closed loop through thevaporizer to vaporize the fuel;

c. a heat exchanger in the circulating means for exchanging heat energybetween the working fluid and air to cool the passenger compartment ofthe vehicle;

d. pump means of the circulating means to circulate the working fluid;

e. thermostatic means in temperature communication with the workingfluid outlet of the vaporizer;

f. normally closed valve means in fluid circuit with the circulatingmeans for admitting warm water from the vehicle s cooling system;

g. means between the thermostatic element and the normally closed valvemeans to open the valve when the thermostatic element senses apredetennined temperature approaching the freezing temperature of theworking fluid; and

h. means to discharge working fluid from the circulating means when thenormally closed valve means is open an amount corresponding to theamount of water admitted to the circulating means by the valve means.

6. The system claimed in claim 5 wherein:

a. check valve means is provided in the circulating means between theworking fluid outlet of the vaporizer and the working fluid inlet of theheat exchanger to prevent fluid flow in the direction of the workingfluid outlet of the vaporizer;

warm water from the engine's cooling system to the inlet of the heatexchanger, the check valve being disposed to direct water passingthrough the heat exchanger valve means directly into the inlet of theheat exchanger.

1. A fluid circuit for vaporizing a fuel for a water-cooled engine of a vehicle while cooling or heating a passenger compartment of the vehicle comprising: a. means for storing a source of fuel to be vaporized; b. a vaporizer for vaporizing fuel through heat exchange with a working fluid of engine-cooling water, the vaporizer being in fluid circuit with the fuel-storing means; c. a selectively closed fluid loop circuit for the working fluid; d. a heat exchanger in the loop for exchanging heat energy between the working fluid and air, the heat exchanger being adapted for discharge of such air into the passenger compartment of the vehicle and being in fluid circuit with the vaporizer; e. a pump in the loop in fluid circuit with the vaporizer and the heat exchanger for circulating working fluid around the loop; f. selectively actuatable, normally closed valve means for admitting warm engine-cooling water from the engine to the loop; g. means for recirculating engine-cooling water from the loop to the engine''s cooling system when the valve means is open and after water entering the loop from the engine''s cooling system passes through the heat exchanger and the vaporizer; h. thermostatic element means for sensing the temperature of the working fluid in the loop; i. second selectively actuatable, normally closed valve means for admitting warm engine-cooling water from the engine to the loop; and j. means coupling the thermostatic element means with the second valve means to open the valve means to admit warm enginecooling water into the loop upon the sensing of a predetermined working fluid temperature near its freezing point by the thermostatic element, the recirculating means being operable to pass engine-cooling water from the loop when the second valve means is open.
 2. The circuit claimed in claim 1 wherein the second valve means is disposed in fluid circuit with the loop between the working fluid inlet of the vaporizer and the outlet of the heat exchanger.
 3. The circuit claimed in claim 2 wherein the first valve means is disposed in fluid circuit with the loop between the inlet of the heat exchanger and the working fluid outlet of the vaporizer.
 4. The circuit claimed in claim 3 including check valve means between the recirculating means and the first valve means to prevent water from such valve means from bypassing the heat exchanger.
 5. A system for vaporizing a fuel such as liquid natural gas used to power an engine of a vehicle while providing cooling air to the vehicle''s passenger compartment comprising: a. a vaporizer for vaporizing the fuel as it leaves a fuel container of the vehicle; b. means for circulating a working fluid in a closed loop through the vaporizer to vaporize the fuel; c. a heat exchanger in the circulating means for exchanging heat energy between the working fluid and air to cool the passenger compartment of the vehicle; d. pump means of the circulating means to circulate the working fluid; e. thermostatic means in temperature communication with the working fluid outlet of the vaporizer; f. normally closed valve means in fluid circuit with the circulating means for admitting warm water from the vehicle''s cooling system; g. means between the thermostatic element and the normally closed valve means to open the valve when the thermostatic element senses a predetermined temperature approaching the freezing temperature of the working fluid; and h. means to discharge working fluid from the circulating means when the normally closed valve means is open an amount corresponding to the amount of water admitted to the circulating means by the valve means.
 6. The system claimed in claim 5 wherein: a. check valve means is provided in the circulating means between the working fluid outlet of the vaporizer and the working fluid inlet of the heat exchanger to prevent fluid flow in the direction of the working fluid outlet of the vaporizer; b. recirculating means is included as the discharge means, the recirculating means being between the check valve and the working fluid outlet of the vaporizer for returning working fluid to the cooling system of the engine; and c. heat exchanger valve means is included for admitting warm water from the engine''s cooling system to the inlet of the heat exchanger, the check valve being disposed to direct water passing through the heat exchanger valve means directly into the inlet of the heat exchanger. 